At some point near the end of April (I don't recall the exact day) my computer suddenly began to completely shut itself off after about 15 minutes (sometimes less) of ESO running. I have a macbook from 2013 running OS 10.14. Previously I never had a problem playing ESO on this computer, I usually didn't get myself into intense combat here on the laptop, but it ran perfectly fine for hours of galloping through the landscape collecting skyshards and puttering around town doing crafting writs and checking guild traders. Then suddenly one morning, not right after an update, it just basically stopped working. At first I thought it was related to heat and the fan because it seemed to run ESO until I could hear my fan had reached full speed, then the whole computer would just instantly turn off, no closing down messages, just suddenly black screen and not just asleep, totally off. But then it happened another time when the fan wasn't running at all, ESO was sitting in the background while I'd gotten distracted reading something in a web browser while waiting for ESO to log in. The length of time it will run is not consistent. Sometimes it will shut my computer off almost immediately upon logging in, other times I can do a round of writs before it dies, it's never very long though, not long enough to really accomplish anything or do something with others. It will do this whether I'm on the Character Select screen or actually In the Game. My computer does not turn off like this any time except when ESO is running. HELP! While I can still play on our gaming PC, my husband is often using that so I used to do a lot of ESO on my laptop and I'm really missing it!

Summary
2013 Macbook OS 10.14
the whole computer shuts off when ESO is running for more than about 15 minutes max, often immediately after logging in.